Best integrated tube amplifier, under $3,000.00. No phono needed. Could be used, too.d

The Raven Audio Blackhawk has the best sound out of the box- truly high end rich yet transparent.
If you need more power the Rogue CM II/III can sound nearly as good with some tube rolling of the 5 small signal tubes.  
May have been supporting systems but I did not care for the sound of the Line Magnetic integrated amps.  
The Primaluna sound very good but tend to have a certain flavor to the sound and have too many tubes to deal with for me to bother.  

Here’s Huff’s review of the Line Magnetic amp, which sounds very much like their amps noted above. Though, I think I might even like the LM 518ia, or LM 805ia a bit better.

Huff kinda "goes nuts" over every new amp he reviews. But, you will have a difficult time finding a better sound than any of these Line Magnetic amps. Certainly for their modest price.  

Of course... provided... that you mate them with the right speakers (e.g.  Proac Response D2).

https://www.stevehuffphoto.com/line-magnetic-219ia-integrated-tube-amp-review-300b-and-845-tube-magic/

I can vouch for the Rogue Audio recommendations. I have a Cronus Magnum II and it's great!

It’s a bit of a stretch, but I’d go for the Pathos Acoustics Twin Tower integrated amp just listed this morning 12/7. Ideally, you could negotiate toward your price and hopefully, you are fairly close because I could see it getting damaged in shipping. -No affiliation. Beautiful, excellent sounding Italian hybrid amplifier. (Not Chinese.)

Strong recommendation here for the Audio Research VSi60, which you can probably pick up used in your price range. About 50 watts.

I've owned one, loved it, sold it to a friend who loves it. Have heard it compared to comparably priced Rogues -- blew them away.